For purposes of illustration, the discussion herein will be directed toward the prevention of foaming in sugar beet processing. Briefly, this entails:
Washed sugar beets are brought into contact with beet-slicing mechanisms. These mechanisms are often horizontal axis, rotating drum slicers with serrated knives set in the periphery of the drum. The beets are sliced into cossettes by the beet-slicing mechanisms. Cossettes are long, thin strips, 2-3 mm thick and up to 15 cm long with a V-shaped or square cross section. The cossettes are then transferred into a diffuser for extraction of their sugar. Heated fresh and process water (65.degree.-80.degree. C) passes through the diffuser thereby contacting the cossettes and removing the sugar from the cossettes along with soluble impurities and some solids. As the water leaves the diffuser for further processing, it is termed "raw juice."
The raw juice is then purified, usually by the addition of lime and carbon dioxide gas. The mechanism of purification entails the formation of precipitates of insoluble impurities as well as the coagulation and adsorption of other impurities.
The purified juice is then gradually heated to drive off water thereby forming "thick juice" which is filtered to produce "standard liquor." The standard liquor is then boiled under vacuum, and crystal formation is promoted. Raw sugar crystals thus produced are separated from the mother liquor ("molasses"). The molasses are then usually de-sugared under the Steffen process. This process entails the dilution of the molasses with water, followed by cooling, addition of large amounts of lime and carbonation.
Foaming occurs during beet washing, during treatment in the diffuser, during the purification and evaporation processes, as well as during the Steffen process. Foaming problems are most significant in the diffuser, in the early purification processes and in the Steffen process. In order to enable efficient handling of sugar beet liquor, it is, therefore, necessary to employ antifoaming agents at various points in this sugar beet process.
The control, prevention and destruction of foam produced in the extraction of sugar beets and in other food processing procedures has long been of considerable importance. Antifoaming agents commonly used in the past have included polypropylene glycol and vegetable oils. We have found a new antifoaming agent which is far superior to the antifoaming agents presently commonly employed in food processing.